1. Field of Invention
The present invention relates to a collapsible chair, and more particularly to a tensional seat support arrangement for collapsible chair which provides the user of the collapsible chair with two sides of seat support.
2. Description of Related Arts
Referring to FIG. 1 of the drawings, a conventional foldable chair comprises a foldable chair frame A1 constructed by metal tubes and a seat fabric B1. The foldable chair frame A1 comprises a plurality of construction tubes A11 to construct a back supporting frame A2 and a seat frame A3 for supporting the fabric seat B1. The seat frame A3 comprises a front pair, a back pair, and two side pairs of the construction tubes, wherein each pair of the construction tubes are pivotally connected together where they cross so that the chair frame A1 can be easily unfolded to provide a rigid cross-support for use and be folded up for storage. Since the conventional foldable chair can be quickly and easily unfolded for use and folded into a compact for carriage, the user can carry the foldable chair to everywhere such as campground or beach.
However, the conventional foldable chair has a major drawback. Since the seat portion of the seat fabric B1 is suspendedly supported by the seat frame A3, the seat fabric B1 may not be substantially supported. When the user sits on the seat fabric B1, the downward pulling force is applied on the seat portion of the seat fabric such that the seat portion will be stretched to the center thereof. Therefore, most of the users of the conventional foldable chair have an intention to plunge into the chair frame downwardly.
Besides, stresses are created by the downward pulling force at the connecting joints where the seat fabric B1 is connected with the chair frame A1. The user""s weight causes the seat fabric B1 to be pulled away from the connecting joints such that the stresses will be created at the connecting joints. The stress created will then cause a tear along the area of the seat fabric B1 at the connecting joint so that the seat fabric B1 will be permanently misshapen at the stress point over a period of continuous use.
A main object of the present invention is to provide a tensional seat support arrangement for collapsible chair, wherein the user""s hip and thigh can be well supported such that the collapsible chair is more comfortable and capable of supporting more weight in comparison with the conventional chair frame that has same frame structure and size.
Another object of the present invention is to provide a tensional seat support arrangement for collapsible chair which substantially increases the supporting contact-area of the fabric seat to more evenly distribute and support the downward force and stress applied by the user""s weight.
Another object of the present invention is to provide a tensional seat support arrangement for collapsible chair, wherein two side portions of seat support fabric are substantially supported by two foldable side supporting arms respectively in such a manner that the user is allowed to sit on the fabric seat without distorting the shape of the fabric seat.
Another object of the present invention is to provide a tensional seat support arrangement for collapsible chair, wherein the two side supporting arms do not increase the distance between the front frame legs and the back supporting frame legs, i.e. the folding size of the chair frame. In other words, the collapsible chair of the present invention is adapted for being folded into a compact unit for carriage and storage and unfolded for use as usual.
Another object of the present invention is to provide a tensional seat support arrangement for collapsible chair, which does not require altering the original structural design of the collapsible chair, so as to minimize the manufacturing cost of the collapsible chair incorporating with the tensional support arrangement.
Accordingly, in order to accomplish the above objects, the present invention provides a collapsible chair, comprising:
a chair frame, which comprises a seat frame comprising:
two side frames each comprising a first frame leg and a second frame leg pivotally coupled with each other to form a xe2x80x9cXxe2x80x9d structure,
a front frame comprising a first front frame leg and a second frame leg pivotally coupled with each other to form a xe2x80x9cXxe2x80x9d structure,
a rear frame comprising a first rear frame leg and a second rear frame leg pivotally coupled with each other to form a xe2x80x9cXxe2x80x9d structure,
a pair of front frame joints pivotally connected with two upper ends of the first frame legs and two upper ends of the two front frame legs respectively,
a pair of back supporting frame joints pivotally connected with two upper ends of the second frame legs and two upper ends of the two rear frame legs respectively, and
a back supporting frame comprising a pair of back supporting frame legs upwardly extended through the two back supporting frame joints respectively; and
a tensional support arrangement, which comprises:
a pair of guiding holders provided at the two back supporting frame legs respectively; and
a pair of side supporting arms, which are positioned at two outer sides of the seat frame, wherein each of the side supporting arms has a support portion which front end is pivotally connected to the respective front joint and a guiding portion which is rearwardly extended from the support portion and slidably supported by the respective guiding holder; and
a seat fabric, which is attached to the chair frame by mounting on the front and back frame joints, having two side edge portions substantially supported by the support portions of the side supporting arms respectively.